Several videos have emerged this week, showing Bradley Fighting Vehicles successfully taking on advanced Russian T-90 tanks.
From Special Kherson Cat on Twitter, video of Bradley IFV vs T-90 in Avdiivka
Sunday, January 14, 2024
Saturday, January 13, 2024
Ukraine: Types of Missiles that Russia Commonly Fires at Ukrainian Cities
S-300 / S-400 a potent, long range, surface-to-air, anti-aircraft guided missile, S300 developed in 1978, S400 in 2007. Fully automated, or can be manually piloted. Launched form a command post, which include acquisition and guidance radar, transportation, and launch vehicles. May be used to intercept aircraft or other missiles. Possessed by a number of countries in Europe and the Middle East, and used in conflicts including Syria and Nagorno-Karabakh. Used extensively against ground targets in Ukraine. Image by By Tourbillon - Own work, CC BY 3.0, https://commons.wikimedia.org/w/index.php?curid=6714828. 
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Kh-47 Kinzhal hypersonic air-launched ballistic missiles, NATO name "Killjoy", entered service in 2017, design based on the older Iskander missile, uses standard ballistic missile technology at greater speeds. After launch, the missile rapidly reaches cruising speeds of Mach 4, and up to Mach 10 on a downward trajectory. Maneuverable, erratic flight path. Originally touted as "impossible to intercept" by Russia, Kinzhals have been used extensively in Ukraine, and a significant proportion of them were successfully shot down by Patriot air defense systems in 2023. They have also proven to be fairly inaccurate. Image from By kremlin.ru, CC BY 4.0, https://commons.wikimedia.org/w/index.php?curid=68926303
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Kaliber cruise missile, in service 1994, some models are capable of a supersonic terminal sprint, traves at ~70' over water, or ~150-350' over land, uses inertial guidance +terminal radar or satellite guidance,
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Iskander mobile ground-launched, short-range hypersonic ballistic missile, NATO name "Stone", first launched in 1996, as a replacement to the SCUD missile, uses inertial guidance or GPS, depending on model, can be re-targeted midflight, uses evasive maneuvers and decoys during terminal flight, travels at an altitude of 20,000-160,000 feet. Used in Syria, Georgia, Nagorno-Karabakh, and Ukraine wars. In the summer of 2023, an Iskander was used to destroy Ria Pizzeria, a restaurant in Kramatorsk, Ukraine, frequented by journalists, aid workers, and military members. The famous Ukrainian writer Victoria Amelina was killed, along with a pair of 14-year-old twin sisters, and 10 others. Dozens were injured.
Image from Vitaly V. Kuzmin - http://www.vitalykuzmin.net/Military/ARMY-2016-Demonstration/, CC BY-SA 4.0, https://commons.wikimedia.org/w/index.php?curid=52213498
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Kh-101 / Kh-555 / Kh-55 family of air-launched subsonic cruise missiles, Nato name "Kent", in service 1983, inertial guidance with terminal radar/terrain map, capable of cruising at tree-top level, the original Kh-55 ran on a Ukrainian-made Sich motor, used in Syria and Ukraine wars
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Kh-22 "Storm" missiles. NATO name "Kitchen". Large, long-range anti-ship missile developed in 1962. Climbs to either 89,000' (high-altitude mode) or 39,000' (low-altitude mode), then hits top speed while dropping towards target. Guided by radio altimeter and gyroscope-stabilized autopilot. A 1,000kg shape-charge load results in a 16' wide, 40' deep hole. First combat use was in May of 2022 in Ukraine. Use against targets in civilian areas of Ukraine has been criticized due to low accuracy. Image by By Антон Бородин - Музей авиационной техники, CC BY-SA 3.0, https://commons.wikimedia.org/w/index.php?curid=10658517
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Kh-59 "Ovod" or "Gadfly" guided aerially-launched land-attack cruise missiles. Developed in the 1980's. Flies at about 22' above water, or 300-3,000' above ground, using a radio altimeter. Used in Chechnya and Ukraine.
Notes: "hypersonic" missile is somewhat of a misnomer; nearly all ballistic missiles reach hypersonic speeds at some point during flight
"Kh" and "X" are both transliteration options for the same Russian letter, (X)
Info from Jane's Air-Launched Missiles
Friday, January 12, 2024
Ukraine: Drones and Dogwalking
While GPS, mass consumer production, and AI have revolutionized use of warfare drones in Ukraine, early drones were a feature of many 20th century conflicts. Radio-controlled planes flew in WWI, and the Warsaw Uprising Museum in Warsaw has a display featuring a WWII "Goliath tracked mine" unmanned ground vehicle. Drones have increasingly been utilized in small-scale conflicts of the pre-Ukraine-war 21st century.
In Ukraine, large-scale use of surveillance and attack drones have complicated traditional combined arms warfare. Surprise attacks have become more difficult, and countermeasures, such as armor, avoiding vehicle travel near the front, and signals jamming, have become crucial. Development of ever-more sophisticated drone tactics and countermeasures will be a hallmark of the Ukraine war, throughout its duration.
And, as we see in the video, drones are not just good for war. They are also great for dog-walking.
Thursday, January 11, 2024
Tuesday, January 9, 2024
Aug 2023: 'The Spectator' Article on military medicine in Ukraine
From The Spectator, 23 Aug 2023: 'Ukraine's Real Killing Fields: An Investigation into the War's First Aid Crisis'
In this article, Spectator reporters interview medics from the Hospitallers and the Ukrainian military. Challenges such as military bureaucratic hurdles for replacing medical equipment, corruption, and medical training and staffing shortcomings,
The Spectator is a politically conservative UK magazine. It is the oldest political affairs magazine in print, and its former editors include Boris Johnson and several former UK cabinet members. Until recently the Spectator, along with the Telegraph, was owned by the Barclay Brothers. Back in 2014, the Telegraph Group was criticized for taking Russian funds in exchange for publishing links and supplements of Russian propaganda on Telegraph Group venues. This included reports downplaying Russian involvement in shooting down Flight MH17. These links were later removed. Since the start of the full-scale invasion, the Spectator and the Telegraph have leaned pro-Ukrainian, and have provided a wealth of in-depth reporting on Ukrainian and Russian affairs.
The Telegraph Ukraine reporting and daily hour-long Ukraine podcast
From The Spectator, 23 Aug 2023: 'Ukraine's Real Killing Fields: An Investigation into the War's First Aid Crisis'
Monday, January 8, 2024
Video of hospital in Pokrovsk, Ukraine, at moment of bomb impact
Here is a video posted to the english-language Telegram Channel Live:Ukraine on 9 Feb 2023, allegedly showing a hospital in Pokrovsk, Ukraine, at the moment of a bomb impact.
Friday, January 5, 2024
Ukraine: Air Raid!
A fascinating feature of the Ukraine war is the amount of real-time information (and propaganda) available to civilians. Daily updates are put out on Telegram, Facebook, and other platforms by the Ukrainian Ministry of Defense, Russian Ministry of Defense, and an array of milbloggers. Civilians post videos of rockets and missiles impacting, or being shot down, which provide the opposing side with battle damage assessments and information of air defense locations. Various 3rd-party open-source intelligence groups collate data and publish up-to-date maps of reported Russian and Ukrainian positions. A network of Ukrainian observers and defense agencies provide instant reporting on Aerial threats via a variety of Telegram channels. This includes radar-detected movements and takeoffs of missile-launching platforms such as Tupolev bombers and MIG jets, launches, locations, and vectors of incoming missiles (including hypersonic ballistic Kinzhals and Iskanders, Kaliber cruise missiles, repurposed S-300 surface-to-air missiles, and Shahed drones. Here's a typical series of missile updates from this week, courtesy of the Telegram channel "Radar".
13:57 Attention! There is activity of enemy tactical aviation in the eastern and south-eastern directions! Threat of aerial weapons launch! In case of air raid alarm announcement in your area, seek shelter. - 39,000 views
14:02 Air alarm for Dnipropetrovsk Oblast! - 38,000 views
14:02 Air alarm for Zaporizhya Oblast! - 37,800 views
14:06 X-59 threat for areas where the Alarm is - 38,900 views
14:18 X-59 headed towards Dnipro - 38.600 views
14:19 Dnipro: take shelter! - 39,100 views
14:19 Zaporizhya: take shelter! - 39,600 views
14:19 X-59 Rocket approaching Dnipro Region - 39.800 views
14:21 Dnipro: Explosions - 41,000 views
14:24 The rocket has been destroyed! (by air defense) -41,000 views
Thursday, January 4, 2024
Combat Medicine: Pelvic Fractures
The pelvis has major blood vessels running throug it; fracture or penetrating injury can easily lead to a fatal amount of massive hemorrhage. Pelvic fractures with hemodynamic instability have a 40% mortality. 26% US mil deaths in Afghanistan and Iraq had a pelvic fracture.
Pelvic fractures are generally caused by severe blunt force or blast trauma. Signs and symptoms include:
Pelvic pain and/or crepitus
Deformed or unstable pelvis, unequal leg lengths, or outward rotation of legs (open-book fracture)
Bruising at bony prominences of pelvic ring, anal/vaginal/urethral bruising or bleeding
Neurological deficits in lower extremities
Major lower limb amputation or near amputation
Unconsciousness
Shock
Pelvic binders help return the pelvis to its natural position and lessen bleeding and further damage. There are several purpose-made varieties; an improvised binder may also be made using a sheet or similar object. Pelvic binders should be placed low, at the level of the greater trochanters ("bottom of the patients' pocket openings"). Higher placement can actually leverage open lower-pelvic fractures, increasing damage. One assessment at a major UK trauma center found that 41% of pelvic binders were placed too high. Outward rotation of legs may be observed in displacement pelvic fractures; in these cases legs should also be bound together, in order to prevent further displacement.
An Assessment of Pelvic Binder Placement at a Major UK Trauma Center
Wednesday, January 3, 2024
TCCC
1996 CAPT Frank Butler formalized concepts and experiences from lessons learned in prior conflicts into first TCCC guidelines, and publishes them as an article. These guidelines were presented to DoD leadership, but were not immediately implemented as a universal standard. However, they were adopted by the Naval Special Warfare Command, 75th Ranger Regiment, the Army Special Missions Unit, and Air Force pararescue community.
Medical research efforts by the US Special Operations Command led to the initiation of the 42-member Committee on TCCC (CoTCCC). CoTCCC's mission is “To develop on an ongoing basis the best possible set of trauma care guidelines customized for the tactical environment and to facilitate the transition of these recommendations into battlefield trauma care practice.” CoTCCC membership includes representatives from all service branches, and includes surgical specialists, emergency physicians, combat medical educators, physicians assistants, nurses, and medical planners. At least 30% of the voting membership must be active or former combat medics, paramedics, or pararescuemen. TCCC guidelines are based on evidence-based medicine, not anecdotal instances.
In 2013 CoTCCC was moved under the Joint Trauma System's jurisdication (JTS). JTS was put together in order to improve military care of trauma patients. It has 6 components:
1) DOD Trauma Registry Management
2) Defense Committee on Trauma
3) Performance Improvement
4) Combatant Command Trauma System Management
5) Joint Trauma Education and Training
6) Defense Medical Readiness Institute
JTS develops and maintains Clinical Practice Guidelines, recommending combat casualty care training requirements, evaluating new medical equipment, facilitating medical performance improvements, facilitating collection and sharing of combat casualty data, maintaining the DOD Trauma Registry, and improving the organization and delivery of trauma care.
Some level of TCCC is required for all US service members. The levels are listed below; ASM is the most basic, and CPP is the most advanced.
ASM All Service Members
CLS Combat Lifesaver
CMC Combat Medic/Corpsman
CPP Combat Provider Paramedic
The latest version of TCCC was released in 2020 and can be found here.
Tuesday, January 2, 2024
Tourniquet Conversion
So far, an estimated 25,000-50,000 amputations having already occurred on the Ukrainian side of the war. Patients with tourniquets may not reach definitive care for 24 hours or more after tourniquet placement. Tourniquet times of less than 2 hours have a negligeable impact on limb salvage rates; tourniquet times over 4 hours are associated with reduced limb salvage rates. Amputation of a tourniqueted limb is very likely after 24 hours. Therefore, assessing whether stable patients who arrive at our near-frontline medical facility are candidates for a tourniquet conversion is a priority. "Tourniquet conversion" refers to the process of replacing a tourniquet with a simple pressure dressing.
While civilian prehospital medical personnel are generally taught to never remove a tourniquet once placed, in the US military tourniquet conversion is a basic-level medical intervention. The TCCC guideline, taught to all US military members, is "every effort should be made to convert tourniquets in less than 2 hours if bleeding can be controlled by other means". Temporary tourniquet placement of up to 3 hours, with no resulting tissue damage, is also a common technique used by surgeons.
The process for converting a tourniquet is:
1) pack the wound and apply pressure for 3 minutes
2) apply pressure dressing
3) slowly release tourniquet over 1 minute, watching for bleeding. If bleeding resumes, re-tighten the tourniquet. Re-attempt conversion in 2 hours, as long as it hasn't been more than 6 hours since original application.
4) If conversion is successful, note release time and leave loosened tourniquet on the limb, just above the wound, in case tourniquet re-application is needed later.
Tourniquet conversion is contra-indicated in patients who are in shock, have an amputation below the tourniquet, or who cannot be monitored closely for bleeding. Tourniquets that have been on for more than 6 hours should not be converted. Intermittent reperfusion (Loosening a non-covertable tourniquet temporarily at intervals in an attempt to preserve the limb), is a common surgical technique. However, in field situations without ability to replace lost blood, this is dangerous and ineffective, and not recommended by TCCC.
Impact of time and distance on outcomes following tourniquet use in civilian and military settings: A scoping review
Monday, January 1, 2024
Ukraine: Combat TBIs
TBIs and their sequelae have long been associated with wars.
Brain Neurotrauma: Molecular, Neuropsychological, and Rehabilitation Aspects: Chapter 2: Combat TBI History, Epidemiology, and Injury Modes* by Ralph G DePalma offers a brief and fascinating historic overview, starting with Iliad accounts of TBIs, PTSD, and post-war mental illness from the legendary Trojan War. This chapter contains a wealth of links to pieces on "shell shock" blast injuries of WWI and WWII.
Between 2000-2012, 255,852 US military service members sustained TBIs. 83% of these were mild, and 80% were estimated to have occurred in non-deployed settings, for example during training, sports, or vehicle accidents. A New York Times investigation examined TBI rates amongst US artillery companies who conducted heavy shelling campaigns against ISIS during the 2016-2017 anti-ISIS offensive. Some soldiers fired over 10,000 artillery shells in the space of just a few months. A military-ordered study of Fox battery, 2nd Battalion, 10th Marines, found that half of the unit had sustained TBIs during artillery firing operations. Study of microscopic damage caused by repeated lower-level blast exposures, or "Chronic Traumatic Encephalopathy" (CTE) is a young science. Under pressure from Veteran's groups, between 2018-2022 Congress passed bills ordering the Pentagon to start a large "Warfighter Brain Health Initiative". This initiative will endeavor to measure blast exposure and create protocols to protect troops. A growing pool of data suggests that safe blast exposure levels may be much lower than was previously assumed. The issue of CTE recently featured in the headlines; the brain of Robert Card, a former military grenade instructor who had a sudden onset of psychosis at age 40 and committed a mass shooting in Maine, will be examined for signs of blast-related CTE.
Massive use of heavy artillery in the current Ukraine War (firing up to 7,000 shells/day by the Ukraine side, and up to 60,000/day by the Russians), along with increased blast survivability made possible by modern medicine and armor, has created potential for long-term TBI impacts on a scale not seen since WWII. Heavy use of thermobaric weapons increases the risk of blast-wave injury.
Manpower shortages mean a lack of post-injury recovery time away from the front. Casualties with mild TBIs are often re-subjected to repeated blasts as soon as a day or two post-injury. As these challenges are likely to be seen in other potential future near-peer conflicts, it can be hoped that Ukraine will systematically work to gather data and implement measures to improve TBI outcomes, and share lessons learned with overseas medical practitioners.
In his book, Ralph G. DePalma writes: "Closed blast TBI has been postulated to relate to vascular surge from the thorax through the neck vessels, air embolism, and piezoelectric currents generated between the skull and the shock wave (Johnson, 2010). Viscoelastic dynamic rippling of the skull secondary to the blast has been postulated based on modeling (Moss et al., 2009). Interactions between the advancing shock wave and blast overpressure, the configuration of the skull, and the brain, including its meninges and cerebrospinal fluid, are complex and cause heterogeneous injury patterns including brain swelling, cerebral vasospasm (Armonda et al., 2006), and diffuse axonal injury (DAI) with disruption across attentional networks (Vakhtin et al., 2013)... Kucherov et al. (2012b) postulated a novel mechanism of primary nonimpact blast injury. Calculations show a dramatic shortening the linear scale of the blast shock wave as it passes through brain tissue. The example of a shock wave interacting with water was used, with the assumption that brain tissue’s physical properties, on the whole, are quantitatively similar to the properties of water. CSF is even closer to water in its physical characteristics. The proposed mechanism, based upon the dynamic behavior of phonons in water, predicts the length scale of damage to be ~30–200 nm. This phonon-based model recently has been shown to accurately describe failure waves in brittle solids (Kucherov, 2012a). A shock wave traveling through the brain is characterized by a shock front, which is a thermodynamic boundary between shocked and nonshocked states of water. The shock front thickness depends on several parameters and decreases in dimensions relative to the intensity of the shock or blast. For intense shocks, the shock wave front equals the interatomic spacing in the specific medium of propagation. The difference between the two states, the blast wave front and the blast wave pressure, is that some of the energy gets deposited behind the shock front, causing a change in thermodynamic parameters of pressure, volume (density), and temperature. For intense shocks, the change in these parameters becomes pronounced, predicting nanoscale damage occurring within microseconds, in contrast to acceleration injuries having durations measured in milliseconds."
A TBI can present as loss or alteration of consciousness at the time of the injury, a confused or disorientated state and/or memory loss during the first 24 hours, and/or abnormal brain imaging. GCS of 13-15 characterizes a mild TBI, 9-12 characterizes a moderate TBI, and 3-8 characterize a severe TBI.
A growing body of evidence shows that prehospital care greatly affects outcomes in TBI patients. While the initial trauma sustained by the patient results in a certain level of irreversible brain cell death, additional secondary injury due to hypotension and hypoxia may be preventable during pre-hospital care.
The EPIC project is a collaboration between the University of Arizona, Arizona Department of Public Health, and over 130 Arizona Fire Departments, and ground and air EMS transport services. The goal of the EPIC Project is to "dramatically increase the number of severe TBI victims who survive with good neurologic outcome by thoroughly implementing the national EMS TBI guidelines." EPIC trained 11,000 EMTs and Paramedics, with emphasis on avoiding hypotension and hypoxia, and maintaining eucapnia. 21,852 patients were included in the effort between 2009-2015. After implementation of the EPIC guidelines, patient survival-to-discharge doubled. Survival tripled amongst TBI patients who required intubation.
A 2017 study published in the Annals of Emergency Medicine found that odds of death increased by 2.5x with a single episode of hypoxia <90%, by 3x with an episode of hypotension <90, and by 6.1x in patient with at least one episode of both hypoxia and hypotension. EPIC guidelines call for pre-oxygenation, with the aim of maintaining an O2 level of 100%. This should be done by applying immediate and continuous high-flow O2 via NRB, starting prior to extrication if applicable. In TBI patients, the risks from short-term hyperoxia are dwarfed by the risks from potential hypoxia.
The target capnography reading is 35-45. It is crucial to avoid hyperventilation, which reduces blood flow and oxygenation of brain tissues. A possible exception is during active brain herniation. Current TCCC guidelines still recommend hyperventilation at 20/minute for patients with signs of brain herniation. However, EPIC guidelines recommend against hyperventilation in any situation, having found that it did not enhance survival to discharge in herniating patients, and caused active harm to non-herniating patients who presented with herniation-like signs.
Opiate pain medications and benzodiazepines may cause blood pressure to drop suddenly in patients with compensated shock, and should be used with extreme caution.
Sunday, December 31, 2023
Ukraine: Great PFC Podcast episode
Ukrainian medic Henri talks with the Prolonged Field Care Collective about conditions in Ukraine: most common injury patterns, weather and exposure, access difficulties, Russian drone attacks on medics, trench foot, dressing complex wounds, penetrating pelvic trauma, prevalence of pneumo-hemothorax over tension pneumothorax, body armor selection factors, and more.
Saturday, December 30, 2023
Blood Loss and the Lethal Triad
Symptoms of blood loss:
500 mL - well tolerated, may produce slight tachycardia, equivalent to a typical blood donation volume.
1000 mL - tachycardia over 100
1500 mL - changes in mental status, weak radial pulse, persistant tachycardia, tachypnea
2000 mL - confusion, lethargy, weak radial, tachycardia over 120, tachypnea over 35, might be fatal if not managed properly
2500 mL - unconsciousness, no palpable radial pulse, tachycardia over 140, tachypnea over 35, fatal without intervention
In patients with blood loss, the "Lethal triad"- is a self-reinforcing cycle of acidosis, hypothermia, and coagulopathy.
Acidosis: Reduced circulating blood volume leads to shunting of blood from the periphery to vital organs in the core. Peripheral tissues resort to anaerobic metabolism, which creates lactic acid as a byproduct. This can be worsened by administration of large volumes of non-oxygen-carrying, acidic fluids, such as normal saline (pH 5.5).
Hypothermia: Develops easily and rapidly in trauma patents, even in warm conditions. Anaerobic metabolism, immobility, and other physiological responses to blood loss reduce heat production. Evidence shows that even small drops in body temperature (to 36C / 96.8F) can significantly increase mortality in trauma and burn patients. At core temperatures below 30C / 86F, patients stop shivering and cannot warm up without application of external heat, even if they are well-insulated. It is far easier to prevent hypothermia than to correct it.
Coagulopathy: Clot formation depends on a complex series of pH- and temperature-dependent chemical reactions. Loss of clotting factors due to bleeding, acidosis, and hypothermia all produce coagulopathy, which in turn further exacerbates blood loss, acidosis, and hypothermia.
Preventing the Lethal Triad cycle is crucial; once established, it is difficult to interrupt. Field treatment of patients with significant blood loss should include oxygen, insulation from the ground, covering with blankets/space blankets/ready-heat systems, and placement in a heated environment if possible.
Friday, December 29, 2023
Antibiotics in trauma
Evidence from historical US conflicts makes it clear that early administration of antibiotics in the field improves outcomes for battlefield casualties. Safety profiles are good for field antibiotics used in US combat medicine, and adverse reactions are rare. Currently, moxifloxacin (4th generation flouroquinolone) is the US military oral antibiotic of choice. Ertapenem (a carbapenem) is the parenteral antibiotic of choice. Together, these drugs cover a wide spectrum of potential infectious microbes.
The US Combat Wound Medication Pack contains 400mg moxifloxacin, along with 15mg meloxicam and 500mg acetominophen. The Ukrainian medication pack contains a similar assemblage of pills.
Wednesday, December 27, 2023
Tuesday, December 26, 2023
Giving Blood in the Field: current TCCC recommendations
Due to occasional severe transfusion reactions, whole blood fell out of favor after WWII. Separating blood into components, such as plasma, red blood cells (RBCs), and platelets allowed for a longer shelf life, easier transport and storage logistics, and reduced risk of disease and transfusion reactions. Separate blood components are needed for many medical interventions. An exception, however, is trauma with massive blood transfusion needed. Recent evidence suggests that, for trauma patients in hypovolemic shock, whole blood produces better outcomes.
TCCC recommendations have evolved through combat experience gained in Iraq and Afghanistan during the recent "Global War on Terror" (GWOT). Before the US invasion of Iraq, most forward resuscitation efforts for blood loss centered on providing non-blood products such as Hextend and PLASMA-LYTE. In 2003, TCCC recommended that blood be carried on casevac units if possible. In 2006, this recommendation was updated to specify low-titer type O blood. As ongoing studies demonstrated increased coagulopathy and reduced survival with non-blood product use, in 2014 TCCC moved blood products to the forefront of care for hemorrhagic shock. 2020 TCCC guidelines list whole blood as the "fluid of choice", with crystalloids, Hextend, and PLASMA-LYTE recommended only if blood products are unavailable.
Whole blood for trauma has a number of advantages. It contains clotting factors that are missing from individually packaged blood components, and has a reduced amount of artificial anti-clotting agents (which can lead to coagulopathy). Whole blood is faster and simpler to administer than individual blood products. This can be important during times of high demand on patient caregivers, reducing workload and opportunities for errors. In general, the sooner blood is given, the better the outcomes. A retrospective study of 502 US military combat casualties in Afghanistan between 2012 and 2015 showed that time to initial blood product transfusion was associated with a reduced 24-hour and 30-day mortality.
Non-blood products such as crystalloids, Hextend, and PLASMA-LYTE come with several negative side-effects. They may contribute to the "Lethal triad"- a self-reinforcing cycle of acidosis, hypothermia, and coagulopathy which is hard to interrupt once it sets in. Expanding blood volume without adding RBCs does not increase oxygen-carrying capacity, leading to ongoing lactic acid production via anaerobic metabolism in oxygen-deprived tissues. Normal saline is acidic (pH 5.5) and infusing large volumes can cause acidosis. Lactated ringers is less acidic (pH 6.5), but is slightly hypotonic and some experts believe it may worsen swelling in TBI patients. Even isotonic crystalloids may seep into damaged tissues, rather than stay in the vascular compartment, due to osmotic differences. High-volume unwarmed fluids contribute to hypothermia, which develops easily and rapidly in trauma patients, due to reduced heat generation during anaerobic metabolism, reduced circulating blood volume, immobility, and physiologic responses to blood loss. Clot formation depends on a complex series of pH- and temperature-dependent chemical reactions. Acidosis and hypothermia both produce coagulopathy, which in turn further exacerbates acidosis and hypothermia. Once established, the lethal triad cycle is difficult to interrupt.
The current TCCC-preferred fluid for blood loss replacement in trauma victims is "LTOWB": cold-stored, low-titer O-negative whole blood. The "ABO" blood groups refer to the presence of A-type and B-type antigens on the surface of red blood cells. Most antibodies are only produced after an exposure to an antigen ("sensitization"). For instance, someone with a severe allergy to bees only experiences an allergic reaction after their second bee sting- the first sting merely introduces foreign material that the body that incites antibody production. But, in the case of antibodies that act against A-type and B-type antigens, this is not true. Each person is born with innate A and/or B antibodies, with no foreign blood exposure required. If a patient with type-A blood is given a transfusion of type-B blood, each of the patient's anti-B antibodies will adhere to several type-B antigens in the donor blood. This causes the donor RBCs to clump together ("agglutination"). These clumps block small blood vessels throughout the body. As the cells of clumps break down ("hemolysis"), they release hemoglobin, which can clog the kidneys and result in kidney failure.
Image shows agglutination in a rapid blood-type test.
Those with blood type A innately have A antigens and anti-B antibodies. Those with blood type B have B antigens, and anti-A antibodies. Those with type O blood have no antigens, and both anti-A and anti-B antibodies. Therefore, type-O blood will not produce reactions in people with type A or B blood.
A second transfusion consideration is presence or absence of Rh factor. 85% of Americans are Rh-positive; they have Rh antigens, and therefore will not produce anti-Rh antibodies. Only Rh-negative individuals can produce anti-Rh antibodies, and they only do so after sensitization. Sensitization can occur via pregnancy with an Rh-positive fetus, or via an Rh-mismatched transfusion. In the case of pregnancy, Rh+ cells rarely cross the placenta; exposure may occur during childbirth, and may become an issue if a second pregnancy with an Rh+ fetus occurs. Similarly, a first transfusion with Rh-mismatched blood is not a problem, however a second transfusion or Rh+ pregnancy might cause a reaction.
Low-titer O blood refers to low levels of anti-A and anti-B antibodies in the type-O donor's blood. Titers below <256 are very unlikely to cause transfusion reactions in blood recipients. For massive transfusion purposes, low A/B antibody titers are more important than presence or absence of Rhesus factors (i.e. whether the blood is "O-positive" or O-negative". Because rhesus-negative patients don't develop sensitivity to Rh-positive products until several weeks after exposure, Rh+ blood can be given to Rh- acute trauma patients without significant risk of a transfusion reaction. So, while ABO-mismatched transfusion reactions can be severe, Rh-mismatch is less concerning in acute trauma situations. For acute trauma, low-titer O blood is best. For general medical transfusion applications, O-negative blood is most useful. Generally, people with type-O-negative blood are 'universal donors', and those with type AB-positive are 'universal recipients'.
TCCC Blood Products Order of Preference:
1) "LTOWB" Cold stored low-titer O negative whole blood. This product has had disease testing performed (HIV, HBV, HCV, West Nile, syphilis, HTLV, Chagas), anti-A/B antibody titer <256, and leukocyte reduction. Shelf life is 21-35 days.
2) "FWB" Pre-screened low-titer O fresh whole blood. 16ga IV should be used to collect from the donor; placement of an 18ga in the recipient is sufficient, safe, and encouraged. Shelf life 6-8 hours.
3) Plasma, RBCs, and platelets in 1:1:1 ratio
4) Plasma and RBCs in a 1:1 ratio. Shelf life 1 yr for plasma, 42 days for RBCs.
5) Plasma or RBCs alone. Some countries (including France, Germany, and South Africa) use freeze-dried plasma (FDP) for austere ops; FDP contains fibrinogen and other hemostatic factors.
Care should be used to prevent hypothermia; warm chilled blood before administration and use a filter to remove small clots. Citrate preservative used in blood collection bags binds with the patient's calcium, therefore 1g calcium should be given after administration of the first unit of blood (either 30mL 10% calcium gluconate or 10 mL 10% calcium chloride daily). Give blood until mental status improves, radial becomes palpable, or BP rises above 100.
Monitor for reactions:
1) Anaphylaxis: wheezing, stridor, shortness of breath, hypotension, hives. Give 0.3mg epi + 25mg benadryl and monitor airway. Optionally give 10-40mg methylprednisolone slow IVP.
2) Acute hemolytic reactions: rupture of RBCs and leakage of contents, generally due to blood mismatch. Symptoms include fever, flank pain, and red/brown urine. All 3 are rarely observed together in field, Pain may alternately occur in an arm, chest, or back, DIC may occur. Nausea may preceed other symptoms. Give 25mg benadryl via slow IV push.
Treatment measures for both anaphylactic and hemolytic reactions: immediately stop the transfusion, give normal saline, stabilize the patient, and try another blood product.
The Use of Low Titer Group O Whole Blood in Emergency Medicine
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